The present invention relates generally to the field of organ preservation or perfusion apparatus. More specifically, the present invention relates to a regulated organ containment shipping system that maintains the temperature and level of a dual-layer preservation liquid surrounding the organ during shipment without the need for perfusion or active refrigeration.
The need to maintain organs and tissue in a viable and sterile condition until they can be transplanted is well known. Originally, organs and tissue were simply wrapped in surgical towels and packed in ice in an ice chest to be shipped from one location to another.
Various organ storage devices that utilize ice, ice water or dry ice as a passive coolant have been developed over the years. U.S. Pat. No. 3,810,867 describes a passive coolant dual container system having an organ holding container disposed in and bonded to another compartment that holds the ice and water coolant. U.S. Pat. No. 4,502,295 describes a passive coolant dual container system with multiple inner containers. U.S. Pat. No. 4,530,816 describes a passive coolant dual container system with an insulating sheet having a selected thermal transfer rate separating the ice from the inner container. U.S. Pat. No. 4,576,017 describes a passive dual container system that uses internal blocks and fins to separate the inner container from the dry ice that is used as the passive coolant. U.S. Pat. No. 4,951,482 describes a passive coolant dual container system similar to a thermos having an inner container for carrying an organ in a preservation medium where the inner container is held in a coaxial arrangement within an outer container that houses the cooling fluid. U.S. Pat. No. 4,958,506 describes a passive coolant dual container system in which a heat pump is used to transfer thermal energy between the inner container and the passive ice coolant in the outer container.
PCT Publ. WO 99/35453 describes a temperature regulated dual container passive coolant organ storage system. The system provides for temperature regulation by using air temperature sensors located around the outer container to control the operation of two battery-powered fans in the lid of the outer container. The fans circulate air over crushed ice in the bottom of the outer container which then cools a stainless steel inner container that houses the organ on a stand within the inner container. The organ is double bagged and placed on the stand. The inner container is then sealed and placed on a metal platform in the outer container for shipment. A microprocessor controls the operation of the system and records temperatures during shipment in an associated memory that are displayed on an electronic console on the outside of the lid of the device.
Other types of cooling systems have also been utilized in organ storage devices. For example, U.S. Pat. Nos. 4,292,817, 4,473,637, and 4,745,759 describe organ storage systems that utilize active refrigeration with a cooling liquid being pumped through the system. U.S. Pat. No. 4,723,974 describes a flexible membrane storage system for amputated members in which two chambers in the outer container with different chemicals create the desired cooling when the divider between the chambers is broken and the chemicals are mixed. U.S. Pat. No. 5,434,045 describes a dual container organ storage system in which the inner container is a sealed concave receptacle for the organ having a first airflow chamber that is put inside the outer container having a second airflow chamber and a fan powered by a micro-motor that re-circulates a refrigerant gas through the airflow chambers to keep the system cool.
It is known that maintaining the organ or tissue in an oxygenated environment improves viability. U.S. Pat. Nos. 3,777,507, 3,881,990, 3,995,444, 5,285,657, 5,476,763, and 6,046,046 describe various types of organ storage systems that actively perfuse oxygen into a preservation liquid (such as UW solution) that is pumped around the organ. These active storage devices may also provide for a pumped refrigeration system. U.S. Pat. No. 5,586,438 describes an organ storage system that can utilize either passive/static cooling with cooled preservation solution or active refrigeration and perfusion by incorporating connections for active refrigeration and perfusion of the UW solution. While effective, these type of active organ storage devices are quite complicated and expensive due to the pumping systems that are required.
One type of preservation solution that was initially developed by Kuroda et al. of Kobe University School of Medicine is a dual-layer preservation solution. As described in Transplantation, Vol. 46, No. 3, September 1988, pp. 457-60, the dual-layer preservation solution utilizes a high oxygen carrier perflourochemical (PFC) liquid as a bottom layer with a Euro-Collins (EC) solution as a top layer. The organ floats in a container between the top and bottom layer and oxygen is actively perfused into the PFC bottom layer. The container is maintained at a cold storage condition by placing the container in an ice-water bath. Variations on this original configuration included not perfusing oxygen into the PFC bottom layer and floating the organ in the EC top layer. Kuroda et al., Transplantation, Vol. 49, No. 4, April 1990, pp. 694-96. Another variation involved using a wire net compressor to hold the organ down into the PFC bottom layer. Kuroda et al., Transplantation, Vol. 49, No. 3, March 1990, pp. 648-50.
While the dual-layer preservation solution has worked well in a laboratory or hospital environment for maintaining the viability of organs, little has been done to adapt a portable organ transport system to utilize this dual-layer preservation solution. Typically, a plastic container is used as the inner container of a passive coolant dual container storage system. The plastic container has a lid with a screw down grate that is used to hold the organ in the PFC bottom layer. This plastic container is then placed on a stand in an outer container that is a conventional ice chest with the bottom filled with crushed ice. Although this arrangement is satisfactory, it would be desirable to provide for an organ containment shipping system that was specifically adapted for use with a dual-layer preservation solution.
The present invention is an organ containment shipping system having an outer container adapted to receive a passive cooling medium and an inner container adapted to receive an organ to be transported in a preservation medium. The inner container is positioned within the outer container by structure that includes a gimbal mechanism to substantially maintain the inner container in a predefined orientation in the event of a change of orientation of the outer container. Preferably, the preservation medium is a dual-layer preservation liquid having a bottom oxygen carrying layer and a top layer. The inner container includes a perforated plate positioned in the inner container above a level of the bottom layer to prevent the organ from rising in the preservation medium.
In one embodiment, the organ containment shipping system includes a system for regulating a level of the preservation medium relative to the organ and a system for regulating a temperature of the organ relative to the cooling medium. Preferably, the system for regulating the level of the preservation medium includes an inlet port having an inlet tube extending into the inner container below the perforated plate and an outlet port defined in a top of the inner container such that the level of the bottom layer can be adjusted by introducing or withdrawing fluid for the bottom layer through the inlet port. Preferably, the system for regulating the temperature of the organ relative to the passive cooling medium includes at least one fan operably connected to an electronic module that houses at least one battery and circuitry. The circuitry is connected to at least one sensor that activate the fans when the sensor indicates that the temperature has risen above a first predetermined level and deactivates the fans when the sensor indicates that the temperature has fallen below a second predetermined level.